The invention is related to a bicycle frame, in particular to a bicycle frame having a removable down tube, the down tube having removable clips on both ends for easy attachment to and removal from a frame and for separate replacement of the down tubes and clips.
A bicycle frame having a removable down tube was previously disclosed in Applicant's Co-pending U.S. patent application Ser. No. 13/380,726, filed Jun. 28, 2010 the entire disclosure of which is incorporated by reference herein. As discussed in that application, there are several advantages to a bicycle having a flexible down tube that can be removed and replaced with a down tube having different characteristics. The replacement of the down tube allows for the modification of the flex characteristics of the frame as well as physical characteristics, such as head tube and seat tube angle, wheel base, and bottom bracket height.
Another advantage of being able to replace a down tube is related to aesthetic appeal. Riders may desire the ability to change out an existing down tube for a down tube having a different style, color, or pattern. It would be expensive and often impractical to purchase a whole new frame just to get a tube with a different look. The ability to change out just the down tube makes a significant change in the appearance of the frame more affordable.
There have, however, been some difficulties associated with previous designs. The set-ups used for previous removable down tubes have, at times, made it somewhat difficult for riders to change out down tubes quickly and easily. What is needed is an improved construction and method for mounting a removable down tube that facilitates replacement of the down tube while maintaining the secureness of the down tube connection and preserving the flex characteristic of the down tube.
Another object of the present invention is to provide a down tube with easily replaceable end fittings or clips in the ends of the down tube such that end fittings and down tubes can easily be replaced separately, without the expense of replacement of both components at the same time. These and other objects are achieved with the improved frame construction of the present invention.